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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #379396
Research Project: Genetic Characterization for Sugar Beet Improvement

Location: Sugarbeet and Bean Research

Title: Azoxystrobin sensitivity of Rhizoctonia solani AG2-2 populations affecting Michigan sugar beet

Author
item WILBUR, JAIME - Michigan State University
item BLOOMINGDALE, CHRIS - Michigan State University
item PINCUMBE, CAMERON - Michigan State University
item HENDERSHOT, CARLY - Michigan State University
item MINIER, DOUGLAS - Michigan State University
item Hanson, Linda

Submitted to: American Society of Sugarbeet Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2021
Publication Date: 2/28/2021
Citation: Wilbur, J.F., Bloomingdale, C., Pincumbe, C., Hendershot, C., Minier, D.H., Hanson, L.E. 2021. Azoxystrobin sensitivity of Rhizoctonia solani AG2-2 populations affecting Michigan sugar beet [abstract]. American Society of Sugarbeet Technologists. 58:104.

Interpretive Summary:

Technical Abstract: Rhizoctonia root and crown rot (RRCR) is caused by Rhizoctonia solani, primarily AG 2-2, and continues to be a major disease of sugar beets. In Michigan, azoxystrobin (Quadris) is widely applied one to two times per season to manage RRCR. Azoxystrobin, a quinone outside inhibitor, targets a single site to inhibit fungal respiration and so possesses a high risk of fungicide resistance development. Continued reliance on this product has justified recent investigations of azoxystrobin sensitivity in Michigan R. solani populations. From 2018-2019, isolates were collected from research and commercial fields in the Michigan sugar beet growing region. Two additional baseline isolates, collected prior to azoxystrobin use in sugar beet, were included for comparison. Isolates were screened in half-strength clarified V8 broth amended with salicylhydroxamic acid at 10 µg ml-1 and azoxystrobin at concentrations: 0, 0.01, 0.1, 1, 10, and 100 µg ml-1. Percent inhibition was calculated and effective concentrations for 50% inhibition of colony mass were determined using three-parameter logistic regression. In 2019, high frequencies of Fusarium spp. and Geotrichum sp. were also isolated from root samples; further molecular and morphological characterization will be conducted with these. Thus far, azoxystrobin insensitivity has not been observed in Michigan R. solani populations, however, additional testing is ongoing. In addition, evaluation of azoxystrobin efficacy, and potential alternatives, for RRCR management was conducted at the Saginaw Valley Research and Extension Center in Frankenmuth, Michigan.